Grails default sort of "hasMany" domain attributes

Question

I'm trying to set default sort of my hasMany attribute using mapping statement. I'm following the grails doc but it doesn't work for me (grails 1.3.5). My code looks like:

class Note {
    Calendar    sendDate
    static belongsTo = Message
}

class Message {
    static  hasMany = [notes: Note]
    static mapping = {
        notes sort:'sendDate desc'
    }
}

The error message looks like:

...
Caused by: com.mysql.jdbc.exceptions.jdbc4.MySQLSyntaxErrorException: Unknown column 'notes0_.sendDate' in 'order clause'
        at com.mysql.jdbc.Util.handleNewInstance(Util.java:409)
        at com.mysql.jdbc.Util.getInstance(Util.java:384)
...

Do you see any mistakes in my code?

Answer 1

A couple things that may help fix the problem:

• Do you really need to use a Calendar for the sendDate property? Most of the time, one would use a java.util.Date. Does changing the field type to a Date fix the issue?

• I ran an example with your mappings and got an error. Try changing your Message static mapping closure to this:

  static mapping = {
      notes sort: 'sendDate', order: 'desc'
  }
  

Answer 2

This page tells all about Object Relational Mapping, I had a similar problem with my app. I solved it like so:

class Note implements Comparable {
  Calendar sendDate
  static belongsTo = Message

  int compareTo(obj) {
    sendDate.compareTo(obj.sendDate)
  }
}

and

class Message {
  SortedSet notes
  static  hasMany = [notes: Note]
}

Hope this helpes!